Modem personal computers can be augmented with hardware and software such that the personal computer can control other home devices such as televisions, video recorders, lights, heating and air conditioning systems, and other similar devices. As such, the personal computer's powerful computing environment allows a wide variety of device control features. For example, the personal computer could be implemented using a single command feature “Watch Video.” This feature could cause the television, video recorder, and audio system to turn on, the video recorder to begin playing, and the television and audio system to select the proper input channel. Further, the lights in the room can be turned down by the processor to provide a more enjoyable viewing environment.
The personal computer typically controls external devices using the control protocol supported by each device. Several different control protocols are currently available. Although many external devices use different control protocols, the personal computer is capable of controlling a wide variety of devices by simultaneously supporting multiple control protocols.
The most common classes of controllable devices in households today are consumer electronic devices such as televisions, VCRs, stereo equipment, and home theater systems. Most consumer electronic devices support Consumer Infrared (IR) which consists of numerous proprietary control protocols. Consumer IR allows consumer electronic devices to be remotely controlled using a hand-held remote. For example, a user can change channels on a television by pressing the “Channel Up” button. When this button is pushed, the remote control sends an infrared command to the television, and the television increments its channel.
Infrared transmitter hardware can be added to personal computers (PC) to control consumer electronic devices. This allows the PC to mimic remote controls of various CE devices. Thus, the PC can autonomously control CE devices. However, a problem is encountered in controlling current consumer electronic devices. Specifically, Consumer IR assumes that a person controlling the consumer electronic device is able to observe the present state of the device, and adjust the command sequence accordingly. For example, most video recorders support a single “Power” command. This command changes the power state of the device, such that if the video recorder is off, the power command turns the device on. Likewise, if the video recorder is turned on, the power command turns the device off. Therefore, in order to get a device (e.g. the VCR) into a particular power state (on or off) it is essential that the person controlling the device know whether a consumer electronic device is already turned on. Similarly, to fully control consumer electronic device operations, a personal computer adapted to transmit IR commands needs to know the present state of the consumer electronic device.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for a system and method of determining an operating state of a consumer electronic device such that it can be controlled by a personal computer.